Extended Data Fig. 6: Integrin-ECM ligand tension precedes FAK activity.
From: Polarized focal adhesion kinase activity within a focal adhesion during cell migration
a Diagram of 19 pN DNA-based MTFM probes and FAK-SPARK activation mechanism. b Representative cell RICM (gray) and fluorescence micrographs of 19 pN hairpin tension(red), IFP2-Paxillin(magenta), and FAK-SPARK(green) at t = 0.0 min. Scale bar, 5 μm. c Overlayed kymographs, yellow line in d, of tension, FAK-SPARK, and paxillin channels. Yellow arrows denote the point of tension and paxillin recruitment and FAK-SPARK droplet formation respectively. d Individual fluorescence micrographs of yellow inset in b at different timepoints, yellow dotted line denotes the linear ROI used for kymograph analysis in (c). Scale bar, 2 μm. e Plot of normalized maximum fluorescence over time derived from the kymograph, with threshold points used to derive the time delay denoted with black circles f Histogram of time delay measurements yielding 21.0 ± 9.0 min average delay between 19 pN integrin tension and FAK-SPARK droplet formation. n = 19 focal adhesions from 4 cells on 4 different surfaces (4 biological replicates).
